Yamaha F40

crestlinermusky

Petty Officer 2nd Class
Joined
May 9, 2010
Messages
102
Hey There, writing for a friend that has a 2015 Yamaha F40 4 stroke that has water in the oil sump. when it was started this summer all that was heard was the knocking the engine was making. When we removed the cover the engine pan was full of water. So with that said it was parked for the season, now that the colder weather has arrived we are going to open it up. This is what we initially found with a compression test, cyl #1 123, cyl # 2 128, cyl # 3 135. Before I go further I would like any thoughts on this, I am thinking block is cracked bad
 

boscoe99

Senior Chief Petty Officer
Joined
Aug 22, 2013
Messages
791
What kind of thoughts? Thoughts related to water in the oil? My first guess would be a failed gasket.

Now where is the water? Just in the lower cowling? Just in the oil pan? Or both?
 
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